Paper Title
EXPERIMENTAL INVESTIGATION OF WAIST-WIDTH VARIATION EFFECTS ON THE PERFORMANCE OF A TWIN-LOBE ROOTS BLOWER

Abstract
Roots twin-lobe blowers are used for pneumatic constituents, wastewater treatment, and air handling in several industrial applications primarily due to their ability to maintain constant airflows while working within large operational windows. The rotor design of the blower is one of the most critical parameters that affect blower performance through pressure generation, air leakage, airflow characteristics and overall consumption of energy. This research evaluated the impact of rotor design and its influence on the operational and performance characteristics of twin-rotor blowers through testing.The author created unique rotors with a three-segment mathematical formulation of circular arc, involute, and tip arc segments. Four variations of the rotor were created by changing the width of the waist (thinner or wider) while still preserving the operational environment of the blower and overall blower geometry. The design configurations for the four rotary devices were analyzed using computer-aided design (CAD) software and manufactured using precision machine tools. All rotary devices were tested using a standardized blower performance test rig to measure discharge pressures, volumetric flow rates and power requirements for generating the discharge pressures.Results indicated that design creates substantial differences in rotor performance; the configuration with the waist width of 23.835 mm (Configuration #1) produced the best overall performance with a discharge pressure of 1.087 × 10⁵ Pa and a volumetric flow rate of 1146 m³/hr, with a maximum gain of 3.32% over the standard rotor. Additionally, results also demonstrated that power requirements for producing the 1.087 × 10⁵ Pa were reduced by 3.05%. The increased performance was attributed to the improved sealing, reduced internal leakage, and minimized backflow characteristics of the rotor profile. Thus, optimizing the rotor profile is an effective way to enhance efficiency and performance of twin-lobe Roots blowers. Keywords - Twin-Lobe Roots Blower, Rotor Geometry, Experimental Investigation, Volumetric Efficiency, Flow Rate, Pressure Ratio, Performance Optimization.